1. Field of the Invention
The present invention relates to an intake device of an internal combustion engine.
2. Description of the Prior Art
In order to improve the volumetric efficiency and increase the output power of an engine, it is desirable that cold air be supplied to the engine cylinders. To this end, in one type of conventional motor vehicle, the air suction inlet of the air cleaner is placed in the low temperature region of the engine compartment so that engine compartment air having as low a temperature as possible can be fed to the engine cylinder. In another type of conventional motor vehicle, the air suction inlet of the air cleaner is placed in front of the radiator so that cold outside air can be fed into the engine cylinders.
However, if the air suction inlet of the air cleaner is placed so that engine compartment air is fed to the engine cylinders as mentioned above, since this air is heated by the engine, air having a relatively high temperature is fed into the engine cylinders. This means that a satisfactorily high volumetric efficiency cannot be obtained.
On the other hand, if the air suction inlet of the air cleaner is placed in front of the radiator, cold outside air is fed into the engine cylinders, making it possible to obtain a high volumetric efficiency. However, in this case, since the air suction inlet of the air cleaner is placed in front of the radiator, foreign matter such as snow flakes, rain water droplets, and dust enter the air cleaner via the air suction inlet thereof. This causes wetting and clogging of the air cleaner element, increasing the flow resistance of the intake air.